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1.
Regul Toxicol Pharmacol ; 126: 105028, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34481892

RESUMO

Analysis of spontaneous reports of adverse events is an important source of information that can be used to improve consumer products. Various agencies have adverse event reporting requirements and many companies collect such data directly from consumers. Nonetheless, a universal framework is absent that identifies and evaluates spontaneously reported adverse events, and, most important, assesses the potential association between exposure and adverse events. We are presenting a three-part framework: Phase I - Intake and Documentation of Original Incidents; Phase II - In Depth Review and Follow-up of Phase I Incidents (enhanced, tailored questionnaire); Phase III - Association Assessment. The basis for scoring the strength of association between exposure and adverse events requires assessment of standard factors of association including: temporality; biological, physiological, or pharmacological plausibility; results of de-challenge; results of re-challenge; and consideration of confounding factors. Scores tied to the answers to these questions are totaled for each incident to determine the strength of association between exposure and reported adverse event. We propose that consumer product companies come together to adopt such an association assessment framework to improve adverse event management, obtain maximum value from the data obtained, and use the knowledge derived to improve overall product safety for consumers.


Assuntos
Qualidade de Produtos para o Consumidor/normas , Vigilância de Produtos Comercializados/métodos , Vigilância de Produtos Comercializados/normas , Sistemas de Notificação de Reações Adversas a Medicamentos/normas , Documentação , Estados Unidos
2.
Gac Med Mex ; 156(6): 516-522, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33877105

RESUMO

INTRODUCTION: Most children affected by SARS-CoV-2 are reported to be asymptomatic, and COVID-19-related mortality in them is low; in Mexico, there is a lack of information on the subject in this population group. OBJECTIVE: To assess the risk factors associated with mortality in Mexican children with COVID-19. METHOD: Secondary analysis of the General Directorate of Epidemiology database. Children younger than 19 years, in whom SARS-CoV-2 infection was confirmed by RT-PCR, were included. RESULTS: 1443 children were included. Median age was eight years; 3.3 % were admitted to the intensive care unit, 1.8 % required assisted mechanical ventilation, and mortality was 1.9 %. In multivariate models, the development of pneumonia was the main risk factor for mortality, with an odds ratio (OR) of 6.45 (95 % CI: 1.99, 20.89); patients who required intubation had an OR of 8.75 (95 % CI: 3.23, 23.7). CONCLUSIONS: Children with COVID-19 exhibit high mortality in Mexico, and avoiding pneumonia should therefore be tried in them, especially in children younger than four years, with cardiovascular risk or immunosuppression. INTRODUCCIÓN: Se informa que la mayoría de los niños afectados por SARS-CoV-2 cursan asintomáticos y que en ellos la mortalidad por COVID-19 es baja; en México se desconoce la información al respecto en este grupo de la población. ­. OBJETIVO: Evaluar los factores de riesgo asociados a mortalidad en niños mexicanos con COVID-19. MÉTODO: Análisis secundario de la base de datos de la Dirección General de Epidemiología. Se incluyeron niños menores de 19 años, en quienes se confirmó SARS-CoV-2 mediante RT-PCR. RESULTADOS: Se incluyeron 1443 niños. La mediana de edad fue de ocho años; 3.3 % ingresó a la unidad de cuidados intensivos, 1.8 % requirió ventilación mecánica asistida y la mortalidad fue de 1.9 %. En los modelos multivariados, el desarrollo de neumonía constituyó el principal factor de riesgo de mortalidad, con razón de momios (RM) de 6.45 (IC 95 % 1.99, 20.89); los pacientes que requirieron intubación tuvieron RM de 8.75 (IC 95 % 3.23, 23.7). CONCLUSIONES: Los niños con COVID 19 tienen alta mortalidad en México, por lo que en ellos se debe procurar evitar la neumonía, especialmente en los menores de cuatro años, con riesgo cardiovascular o inmunosupresión.


Assuntos
COVID-19/epidemiologia , Unidades de Terapia Intensiva/estatística & dados numéricos , Pneumonia Viral/epidemiologia , Respiração Artificial/estatística & dados numéricos , Adolescente , Fatores Etários , COVID-19/complicações , COVID-19/mortalidade , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , México/epidemiologia , Pneumonia Viral/virologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Risco
3.
Science ; 258(5089): 1780-4, 1992 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-1465613

RESUMO

In order to function, transcription factors must compete for DNA binding with structural components of chromatin, including nucleosomes. Mechanisms that could be used in this competition have been characterized with the use of the DNA binding domain of the yeast GAL4 protein. The binding of GAL4 to a nucleosome core resulted in a ternary complex containing GAL4, the core histone proteins, and DNA. This ternary complex was unstable; upon the addition of nonspecific competitor DNA, it dissociated into either the original nucleosome core particle or GAL4 bound to naked DNA. Nucleosome core destabilization by GAL4 did not require a transcriptional activation domain. These data demonstrate the displacement of nucleosome cores as a direct result of binding by a regulatory factor. Similar mechanisms might affect the establishment of factor occupancy of promoters and enhancers in vivo.


Assuntos
Proteínas Fúngicas/metabolismo , Nucleossomos/metabolismo , Proteínas de Saccharomyces cerevisiae , Fatores de Transcrição/metabolismo , Sequência de Bases , DNA/genética , DNA/isolamento & purificação , DNA/metabolismo , Proteínas de Ligação a DNA , Eletroforese em Gel Bidimensional , Eletroforese em Gel de Poliacrilamida , Proteínas Fúngicas/isolamento & purificação , Células HeLa , Histonas/isolamento & purificação , Histonas/metabolismo , Humanos , Dados de Sequência Molecular , Oligodesoxirribonucleotídeos , Reação em Cadeia da Polimerase/métodos , Ligação Proteica , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Fatores de Transcrição/isolamento & purificação
4.
Science ; 208(4451): 1471-3, 1980 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-7189903

RESUMO

Three Siamese cats were found to have a progressive neurological disease that became obvious when they were 4 to 5 months of age. Their brains contained an excess of GM2 and GM3 gangliosides, and their livers a nine- to tenfold excess of sphingomyelin and cholesterol. A total deficiency of lysosomal (pH 5.0) sphingomyelinase was found in the leukocytes, liver, and brain of the cats, although the activity of the microsomal (pH 7.4, magnesium-dependent) sphingomyelinase was normal in brain. These cats appear to have a genetic disease identical to Niemann-Pick disease type A.


Assuntos
Doenças do Gato/genética , Modelos Animais de Doenças , Doenças de Niemann-Pick/genética , Animais , Encéfalo/enzimologia , Química Encefálica , Doenças do Gato/enzimologia , Gatos , Gangliosídeos/análise , Humanos , Cinética , Fígado/análise , Doenças de Niemann-Pick/enzimologia , Fosfolipídeos/análise , Esfingomielina Fosfodiesterase/análise
5.
Science ; 207(4429): 434-9, 1980 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-17833555

RESUMO

An imaging photopolarimeter aboard Pioneer 11, including a 2.5-centimeter telescope, was used for 2 weeks continuously in August and September 1979 for imaging, photometry, and polarimetry observations of Saturn, its rings, and Titan. A new ring of optical depth < 2 x 10(-3) was discovered at 2.33 Saturn radii and is provisionally named the F ring; it is separated from the A ring by the provisionally named Pioneer division. A division between the B and C rings, a gap near the center of the Cassini division, and detail in the A, B, and C rings have been seen; the nomenclature of divisions and gaps is redefined. The width of the Encke gap is 876 +/- 35 kilometers. The intensity profile and colors are given for the light transmitted by the rings. A mean particle size less, similar 15 meters is indicated; this estimate is model-dependent. The D ring was not seen in any viewing geometry and its existence is doubtful. A satellite, 1979 S 1, was found at 2.53 +/- 0.01 Saturn radii; the same object was observed approximately 16 hours later by other experiments on Pioneer 11. The equatorial radius of Saturn is 60,000 +/- 500 kilometers, and the ratio of the polar to the equatorial radius is 0.912 +/- 0.006. A sample of polarimetric data is compared with models of the vertical structure of Saturn's atmosphere. The variation of the polarization from the center of the disk to the limb in blue light at 88 degrees phase indicates that the density of cloud particles decreases as a function of altitude with a scale height about one-fourth that of the gas. The pressure level at which an optical depth of 1 is reached in the clouds depends on the single-scattering polarizing properties of the clouds; a value similar to that found for the Jovian clouds yields an optical depth of 1 at about 750 millibars.

6.
Trends Biochem Sci ; 25(11): 548-55, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11084367

RESUMO

The regulated alteration of chromatin structure, termed 'chromatin remodeling', can be accomplished by covalent modification of histones or by the action of ATP-dependent remodeling complexes. A variety of mechanisms can be used to remodel chromatin; some act locally on a single nucleosome and others act more broadly. It is critical to establish a direct connection between the remodeling events observed in vivo and the mechanistic capabilities of remodeling complexes in vitro.


Assuntos
Cromatina/química , Cromatina/metabolismo , Proteínas de Drosophila , Regiões Promotoras Genéticas , Proteínas de Ligação a RNA , Proteínas de Saccharomyces cerevisiae , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Cromatina/genética , Proteínas de Ligação a DNA , Desoxirribonucleases de Sítio Específico do Tipo II/genética , Desoxirribonucleases de Sítio Específico do Tipo II/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico HSP70/metabolismo , Histonas/genética , Histonas/metabolismo , Humanos , Ribonucleoproteína Nuclear Pequena U1/genética , Ribonucleoproteína Nuclear Pequena U1/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Leveduras/genética
7.
Biomol NMR Assign ; 13(1): 195-199, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30680534

RESUMO

Menangle virus is a bat-borne paramyxovirus with zoonotic potential. The single-stranded RNA genome of the virus is encapsidated in a helical nucleocapsid which is the template for both transcription and genome replication. Each of these operations is performed by the viral RNA polymerase. The phosphoprotein is the non-catalytic subunit of the polymerase, and its C-terminal region enables the polymerase to engage with the nucleocapsid. Here, we report the 1H, 15N, and 13C chemical shift assignments of the C-terminal region (amino acids 267-388) of the Menangle virus phosphoprotein. This region has a bipartite character, with a highly flexible and structurally disordered sequence preceding a structured nucleocapsid-binding domain. NMR chemical shift assignment will enable the detailed characterization of the dynamic behavior of the phosphoprotein, and its functional linkage with polymerase translocation.


Assuntos
Ressonância Magnética Nuclear Biomolecular , Paramyxoviridae/química , Fosfoproteínas/química , RNA Viral/química , Estrutura Secundária de Proteína , Temperatura
8.
Ir Med J ; 101(6): 173-4, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18700510

RESUMO

Knowledge of the number and type of injuries attending the paediatric orthopaedic outpatients is crucial in the future planning of any new paediatric hospital. We prospectively collected data on all new patients attending two paediatric orthopaedic out-patients departments, over a four month period. There were a total of 1,791 completed questionnaires. Sporting and recreational injuries represented 270% and 28% of the total attending, respectively. The new use of heelies represented 11% of the recreational injuries. The upper limb injuries represented 74% of the total, with the lower limb accounting for 25%. Treatment was nonoperative or operative. The number of patients, and the types of injuries presenting demonstrates the workload involved in diagnosing and treating these injuries. A total of 827 casts were applied. With almost half of those attending the clinic requiring a cast, the workload on the plaster technicians is substantial, and has implications for future service planning.


Assuntos
Acidentes/estatística & dados numéricos , Traumatismos em Atletas/epidemiologia , Hospitais Pediátricos/estatística & dados numéricos , Recreação , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Irlanda/epidemiologia , Masculino , Pacientes Ambulatoriais/estatística & dados numéricos , Estudos Prospectivos , Inquéritos e Questionários
9.
Forensic Sci Int ; 283: 29-34, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29247980

RESUMO

Fatty acid ethyl esters (FAEE) are direct metabolites of ethanol and have been shown to be suitable markers for the evaluation of alcohol consumption. Previous research has suggested that the regular use of alcohol containing cosmetic products can influence the concentration of FAEE detected in hair. In this study we investigated the influence of alcohol containing and alcohol free hair cosmetics (hairspray and waxes) on the FAEE concentrations in hair. The effect of cosmetic treatment was measured against the impact on ethyl palmitate in isolation as compared to the sum of four esters. 10 volunteers treated part of their scalp with cosmetic products every day during a 2 month period (alcohol free hairspray n=2, hairspray containing alcohol (42% by volume) n=3, alcohol free wax n=2, wax containing alcohol (11% by volume) n=3). After the 2 month period of cosmetic application hair samples from volunteers were collected from both sides of the scalp. Hair samples were washed with n-heptane, and then cut finely into small pieces. All samples were subjected to clean-up by HS-SPME and then GC PCI-MS/MS for analysis of FAEEs. Comparison of FAEE concentrations between treated and untreated hair showed in some instances that application of hair spray or wax products caused an increase in FAEE levels. Products containing alcohol caused a more substantial increase in alcohol metabolite concentrations in hair when compared to alcohol free products. Three volunteers using an alcohol based hairspray in the study experienced a significant increase in FAEE levels (+27.4%, +205.5%, and +1287.5%), with one of the volunteers showing levels below the cut off for 'abstinence' in the untreated scalp portion, and levels above the cut off for 'chronic excessive consumption' in the treated scalp portion. Performance evaluation of ethyl palmitate as sole marker, compared to the sum of four esters approach suggested that the two quantification approaches react in a very similar manner to the application of hair sprays and waxes. We would suggest that the interpretative value of FAEE hair measurements from people reporting the use of alcohol based hairsprays are treated with caution.


Assuntos
Etanol/análise , Etil-Éteres/análise , Ácidos Graxos/análise , Preparações para Cabelo/química , Cabelo/química , Solventes/análise , Adolescente , Adulto , Biomarcadores/análise , Criança , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Masculino , Ácidos Palmíticos/análise , Microextração em Fase Sólida , Adulto Jovem
10.
Curr Biol ; 4(4): 325-32, 1994 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-7922341

RESUMO

In recent years, many components involved in promoter-specific transcriptional activation in eukaryotes have been identified and characterized. We argue that a proper understanding of transcriptional activation will require quantitative modeling and we outline some of the considerations that such modeling will need to take into account.


Assuntos
Modelos Genéticos , Ativação Transcricional , Animais , Cromatina/metabolismo , Células Eucarióticas , Humanos , Cinética , Substâncias Macromoleculares , Conformação Molecular , Células Procarióticas , Regiões Promotoras Genéticas , Fatores de Transcrição/metabolismo
11.
Psychopharmacology (Berl) ; 194(2): 151-9, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17554526

RESUMO

INTRODUCTION: The ability to read facial expressions is essential for normal human social interaction. The aim of the present study was to conduct the first investigation of facial expression recognition performance in recreational cocaine users. MATERIALS AND METHODS: Three groups, comprised of 21 cocaine naïve participants (CN), 30 occasional cocaine (OC), and 48 regular recreational cocaine (RC) users, were compared. An emotional facial expression (EFE) task consisting of a male and female face expressing six basic emotions (happiness, surprise, sadness, anger, fear, and disgust) was administered. Mean percent accuracy and latencies for correct responses across eight presentations of each basic emotion were derived. Participants were also assessed with the "Eyes task" to investigate their ability to recognize more complex emotional states and the Symptom CheckList-90-Revised to measure psychopathology. RESULTS: There were no group differences in psychopathology or "eyes task" performance, but the RC group, who otherwise had similar illicit substance use histories to the OC group, exhibited impaired fear recognition accuracy compared to the OC and CN groups. The RC group also correctly identified anger, fear, happiness, and surprise, more slowly than CN, but not OC participants. The OC group was slower than CN when correctly identifying disgust. The selective deficit in fear recognition accuracy manifested by the RC group cannot be explained by the subacute effects of cocaine, or ecstasy, because recent and less recent users of these drugs within this group were similarly impaired. Possible parallels between RC users and psychopaths with respect to impaired fear recognition, amygdala dysfunction, and etiology are discussed.


Assuntos
Transtornos Relacionados ao Uso de Cocaína/fisiopatologia , Emoções Manifestas , Medo/psicologia , Reconhecimento Visual de Modelos/fisiologia , Adolescente , Adulto , Consumo de Bebidas Alcoólicas/psicologia , Tonsila do Cerebelo/fisiopatologia , Transtornos Relacionados ao Uso de Cocaína/parasitologia , Expressão Facial , Feminino , Humanos , Masculino , Psicometria/estatística & dados numéricos , Inquéritos e Questionários
12.
Mol Cell Biol ; 10(1): 176-83, 1990 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-2152962

RESUMO

We have analyzed 41 deletion, linker scan, and substitution mutants of the human HSP70 gene promoter for activation by the adenovirus E1a region. No natural element of the HSP70 gene promoter was required for activation. To investigate specific interactions between E1a and transcription factors, a set of 24 promoters containing all possible combinations of eight different upstream or TATA motifs was investigated for E1a stimulation. E1a transactivated the promoter regardless of the particular TATA motif present. Furthermore, there was no dramatic correlation between any upstream motif and activation by E1a. These data suggest that E1a does not stimulate transcription via an interaction with any specific transcription factor but instead suggest that E1a interacts via the general transcription machinery.


Assuntos
Proteínas de Choque Térmico/genética , Proteínas Oncogênicas Virais/genética , Regiões Promotoras Genéticas , Sequências Reguladoras de Ácido Nucleico , Fatores de Transcrição/genética , Proteínas Precoces de Adenovirus , Sequência de Bases , Análise Mutacional de DNA , Regulação da Expressão Gênica , Células HeLa , Humanos , Dados de Sequência Molecular , Vírus 40 dos Símios/genética , Transfecção
13.
Mol Cell Biol ; 10(4): 1319-28, 1990 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-2320000

RESUMO

We have characterized the interactions between the TATA element and other sequence elements of a human heat shock protein 70 (hsp70) promoter by a mutational approach. Expression of a distal element of this promoter requires an intact TATA element in human cell lines. The hsp70 TATA element can be functionally replaced for this interaction by TATA elements from the simian virus 40 early and adenovirus EIIa promoters. The TATA element in this promoter therefore both determines the appropriate start site and determines strength by allowing function of the distal element. In contrast, three proximal upstream elements necessary for basal and heat-regulated transcription have no requirement either for a TATA element or for any other proximal element. The behavior of promoters multiply mutant in these proximal elements implies that these elements function independently. We examined the interaction between the heat shock element (HSE) and the TATA element as the distance between the two factor-binding sites was increased. It was necessary to create a mutant HSE with an extended consensus sequence in order for the HSE to function at a distance. Moving this extended HSE 500 bases upstream did not increase its dependence on the TATA element, suggesting that the TATA independence of this element is intrinsic to its function and is not determined by distance from the promoter.


Assuntos
Proteínas de Choque Térmico/genética , Regiões Promotoras Genéticas , Transcrição Gênica , Animais , Sequência de Bases , Células Cultivadas , RNA Polimerases Dirigidas por DNA/metabolismo , Células HeLa/metabolismo , Temperatura Alta , Humanos , Dados de Sequência Molecular , Mutação , Plasmídeos , Transfecção
14.
Mol Cell Biol ; 10(1): 165-75, 1990 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-2294402

RESUMO

To investigate interactions between transcription factors on mammalian promoters, we constructed a set of 24 variations of the human HSP70 gene promoter in which six upstream sequence motifs are paired in every possible combination with four TATA motifs. These promoters were analyzed for in vivo expression, and selected constructs were examined by in vitro template commitment studies. Activation transcription factor (ATF) and CP1 showed dramatically different interactions with the factor(s) bound to the TATA region. CP1 functioned in vivo regardless of the TATA motif that it was paired with and was not capable of sequestering the core promoter complex in a template commitment assay. ATF activity was dramatically altered by changing the TATA motif, and ATF was able to sequester the core promoter complex. These data suggest that CP1 and ATF function by distinct mechanisms that differ with respect to interaction with the factor(s) at the TATA box. Factor Sp1 also appeared to function by a TATA-independent mechanism. These data imply that the ability of a factor to function is determined not only by the intrinsic properties of the factor but also by promoter context.


Assuntos
Proteínas de Choque Térmico/genética , Regiões Promotoras Genéticas , Sequências Reguladoras de Ácido Nucleico , Fatores de Transcrição/fisiologia , Sequência de Bases , Análise Mutacional de DNA , Regulação da Expressão Gênica , Células HeLa , Humanos , Dados de Sequência Molecular , Moldes Genéticos , Transcrição Gênica , Transfecção
15.
Mol Cell Biol ; 14(3): 1721-32, 1994 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-7906858

RESUMO

The Polycomb group (Pc-G) genes are essential for maintaining the proper spatially restricted expression pattern of the homeotic loci during Drosophila development. The Pc-G proteins appear to function at target loci to maintain a state of transcriptional repression. The murine oncogene bmi-1 has significant homology to the Pc-G gene Posterior sex combs (Psc) and a highly related gene, Suppressor two of zeste [Su(z)2]. We show here that the proteins encoded by bmi-1 and the Pc-G genes Polycomb (Pc) and Psc as well as Su(z)2 mediate repression in mammalian cells when targeted to a promoter by LexA in a cotransfection system. These fusion proteins repress activator function by as much as 30-fold, and the effect on different activation domains is distinct for each Pc-G protein. Repression is observed when the LexA fusion proteins are bound directly adjacent to activator binding sites and also when bound 1,700 bases from the promoter. These data demonstrate that the products of the Pc-G genes can significantly repress activator function on transiently introduced DNA. We suggest that this function contributes to the stable repression of targeted loci during development.


Assuntos
Proteínas de Drosophila , Regulação da Expressão Gênica , Proteínas/genética , Proteínas Repressoras/genética , Serina Endopeptidases , Fatores de Transcrição/genética , Transcrição Gênica , Células 3T3 , Animais , Proteínas de Bactérias/genética , Genes Homeobox , Técnicas In Vitro , Camundongos , Mutagênese Sítio-Dirigida , Oligodesoxirribonucleotídeos/química , Complexo Repressor Polycomb 1 , Proteínas Recombinantes de Fusão/química , Sequências Reguladoras de Ácido Nucleico , Relação Estrutura-Atividade , Transfecção
16.
Mol Cell Biol ; 8(1): 353-60, 1988 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-2961981

RESUMO

We constructed a series of mutations that delete sequences in the promoter region of the early-region IV (EIV) promoter of adenovirus type 5. We fused these promoter mutations to the coding sequences of either the chloramphenicol acetyltransferase or the dihydrofolate reductase (DHFR) gene and tested the ability of a cotransfected EIa gene to stimulate EIV expression. All of the mutations tested were stimulated in these assays, implying that no specific sequence is required for stimulation. Two mutant promoters, deleted for either the TATA box or the region residing between -39 and -177 upstream from the cap site of EIV mRNA, did show a reduced level of stimulation by the EIa products. To assess the effects of the EIA gene products on expression from an EIV promoter integrated into the chromosome, we isolated CHO cell lines containing EIV-DHFR chimeric genes. After introduction of the EIa gene with a second selectable marker, expression from all mutant EIV-DHFR genes was increased. Surprisingly, one mutant promoter, deleted for sequences between -39 and -177, lost the ability to respond to the EIa region on passage of cells, although deletions in any part of the region still retained this ability. These results demonstrate that multiple elements residing between -39 and -177 in the EIV promoter are necessary to maintain susceptibility of the integrated promoter to regulation.


Assuntos
Regulação da Expressão Gênica , Proteínas Oncogênicas Virais/genética , Regiões Promotoras Genéticas , Fatores de Transcrição/genética , Proteínas Virais/genética , Acetiltransferases/genética , Proteínas Precoces de Adenovirus , Animais , Linhagem Celular , Transformação Celular Viral , Cloranfenicol O-Acetiltransferase , Cromatina/ultraestrutura , Cricetinae , Análise Mutacional de DNA , Proteínas Recombinantes de Fusão/genética , Recombinação Genética
17.
Mol Cell Biol ; 7(4): 1530-4, 1987 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-3600634

RESUMO

A factor found in nuclear extracts of human cells bound to the heat shock element of a human heat shock protein 70 gene. The level of this factor was significantly increased after heat shock. This induction was rapid and was not blocked by cycloheximide, suggesting that an initial event in the response of a human cell to heat is the activation of a preexisting regulatory factor.


Assuntos
Proteínas de Ligação a DNA/biossíntese , Genes , Proteínas de Choque Térmico/genética , Regiões Promotoras Genéticas , Sequência de Bases , Núcleo Celular/metabolismo , Células HeLa/metabolismo , Proteínas de Choque Térmico/biossíntese , Temperatura Alta , Humanos , Peso Molecular
18.
Mol Cell Biol ; 11(1): 281-8, 1991 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-1986225

RESUMO

The heat shock response appears to be universal. All eucaryotes studied encode a protein, heat shock factor (HSF), that is believed to regulate transcription of heat shock genes. This protein binds to a regulatory sequence, the heat shock element, that is absolutely conserved among eucaryotes. We report here the identification of HSF in the fission yeast Schizosaccharomyces pombe. HSF binding was not observed in extracts from normally growing S. pombe (28 degrees C) but was detected in increasing amounts as the temperature of heat shock increased between 39 and 45 degrees C. This regulation is in contrast to that observed in Saccharomyces cerevisiae, in which HSF binding is detectable at both normal and heat shock temperatures. The S. pombe factor bound specifically to the heat shock element, as judged by methylation interference and DNase I protection analysis. The induction of S. pombe HSF was not inhibited by cycloheximide, suggesting that induction occurs posttranslationally, and the induced factor was shown to be phosphorylated. S. pombe HSF was purified to near homogeneity and was shown to have an apparent mobility of approximately 108 kDa. Since heat-induced DNA binding by HSF had previously been demonstrated only in metazoans, the conservation of heat-induced DNA binding by HSF among S. pombe and metazoans suggests that this mode of regulation is evolutionarily ancient.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Regulação Fúngica da Expressão Gênica , Proteínas de Choque Térmico/genética , Fosfoproteínas/metabolismo , Sequências Reguladoras de Ácido Nucleico , Saccharomyces cerevisiae/genética , Schizosaccharomyces/genética , Sequência de Bases , Proteínas de Ligação a DNA/isolamento & purificação , Proteínas de Drosophila , Fatores de Transcrição de Choque Térmico , Temperatura Alta , Metilação , Dados de Sequência Molecular , Fosfoproteínas/isolamento & purificação , Fosforilação , Fatores de Transcrição
19.
Mol Cell Biol ; 4(10): 1970-7, 1984 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-6095034

RESUMO

During adenovirus infection, the EII promoter is positively regulated by products of the EIa region. We have studied this regulation by fusing a DNA segment containing the adenovirus EII promoter to a dihydrofolate reductase cDNA segment. Expression of this hybrid gene is stimulated in trans when cell lines containing an integrated copy are either transfected with plasmids carrying the EIa region or infected with adenovirus. This suggests that EIa activity regulates transcription of the EII promoter in the absence of other viral proteins and that this stimulation can occur when the EII promoter is organized in cellular chromatin. Transcription from the EII promoter is initiated at two sites in cell lines lacking EIa activity. Introduction of the EIa region preferentially stimulated transcription from one of these two sites. A sensitive, stable cotransfection assay was used to test for specific EII sequences required for stimulation. EIa activity stimulates all mutant promoters; the most extensive deletion retained only 18 base pairs of sequences upstream of the initiation site. We suggest that regulation of a promoter by the EIa region does not depend on the presence of a set of specific sequences, but instead reflects a characteristic of promoters that have been exogenously introduced into cells. Insertion of the 72-base-pair repeat of simian-virus 40 in cis enhances transcription from the EII promoter. The stimulatory effects of EIa activity and of the simian virus 40 sequence are additive and appear to differ mechanistically.


Assuntos
Adenoviridae/genética , Óperon , Transcrição Gênica , Proteínas Virais/metabolismo , Animais , Sequência de Bases , Cricetinae , Cricetulus , Feminino , Regulação da Expressão Gênica , Plasmídeos , Vírus 40 dos Símios/genética , Tetra-Hidrofolato Desidrogenase/genética , Transfecção
20.
Mol Cell Biol ; 20(17): 6380-9, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10938115

RESUMO

Chromatin remodeling complexes help regulate the structure of chromatin to facilitate transcription. The multisubunit human (h) SWI-SNF complex has been shown to remodel mono- and polynucleosome templates in an ATP-dependent manner. The isolated hSWI-SNF ATPase subunits BRG1 and hBRM also have these activities. The intact complex has been shown to produce a stable remodeled dimer of mononucleosomes as a product. Here we show that the hSWI-SNF ATPases alone can also produce this product. In addition, we show that hSWI-SNF and its ATPases have the ability to transfer histone octamers from donor nucleosomes to acceptor DNA. These two reactions are characterized and compared. Our results are consistent with both products of SWI-SNF action being formed as alternative outcomes of a single remodeling mechanism. The ability of the isolated ATPase subunits to catalyze these reactions suggests that these subunits play a key role in determining the mechanistic capabilities of the SWI-SNF family of remodeling complexes.


Assuntos
Adenosina Trifosfatases/metabolismo , Proteínas de Ciclo Celular , Cromatina/metabolismo , Nucleossomos/metabolismo , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo , Trifosfato de Adenosina/metabolismo , DNA/metabolismo , DNA Helicases , Dimerização , Proteínas de Drosophila , Células HeLa , Histonas/metabolismo , Humanos , Cloreto de Magnésio/farmacologia , Modelos Biológicos , Proteínas Nucleares/metabolismo , Plasmídeos/metabolismo , Cloreto de Potássio/farmacologia , Fatores de Tempo , Transativadores/metabolismo
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